April, 1901. The Island of La Plata — Dorsey. 261 



RECTANGULAR AND CIRCULAR ENGRAVED STONES. 



With equal frequence both in the refuse heaps on the plateau 

 and in the drift earth at its base were large numbers of engraved 

 rectangular and circular stones. 



The stone used for all of the squared and rectangular blocks 

 and for a few other forms which were encountered is a volcanic tuff, 

 grayish white in color. The stones were probably brought to their pres- 

 ent condition by the grinding or rubbing process. The incised lines 

 wereprobably made with some sharp instrument and they are extraordi- 

 narily clean cut. In fact when one first examines one of these lines, 

 so clean is it, there is such a total absence of the scratchings which 

 would have resulted had the line been laboriously incised, one is 

 tempted to believe that the specimens were made of clay and that the 

 lines were engraved while the clay was wet. As a matter of fact, it is 

 probable that when the rock was first quarried it was much softer 

 than it is now, and that the clean cut lines, such as I have described, 

 were made with a single stroke of some sharp-pointed instrument. 



The largest stone measures five inches in length and breadth by 

 two and one-half in thickness, while the smallest measures four inches 

 by four by three and one-half. Of the circular specimens the largest 

 one measures five and one-half inches in diameter by two inches in 

 thickness, while the smallest one measures four and one-half in diam- 

 eter by three inches in thickness. All of these stones (see Fig. 43) 

 are engraved on one side only. This takes the form of two pairs of 

 parallel lines extending, in the squared stones, diagonally across, 

 crossing each other at right angles. The intervening space between 

 the parallel lines varies in one specimen from one and one-fourth 

 inches to one-half an inch in the smallest. In every specimen found 

 the space formed by the parallel lines is occupied either by a series of 

 circles (see PI. XLIV ), or by a series of zigzag lines, or, in one 

 specimen, by both (see PI. XLV). In one instance the parallel lines 

 were three in number,crossing as usual at right angles (PI. XLVI, 

 d), while in still another specimen the parallel lines were four in 

 number ( PI. XLV, i>). In all of the specimens except three the 

 space lying outside of the parallel lines was left vacant. In the three 

 specimens where this was not the case, the space was occupied by 

 one circle in one instance (PL XLV, a), three circles in another 

 (PL XLVII, a) and by four in the third specimen (PI. XLVII, ^). 

 The number of circles or triangles found within the parallel lines varies 

 (see PL XLVIII ) from two to five, four being the most common. 



